Centrifuge apparatus



Aug. 21, 1962 F. e. WILLIAMS, JR

CENTRIFUGE APPARATUS 2 Sheets-Sheet 1 Filed NOV. 20, 1959 FIG.

FRED G WILLIAMS JR INVENTOR.

Aug. 21, 1962 F. G. WILLIAMS, JR

CENTRIFUGE APPARATUS 2 Sheets-Sheet 2 Filed Nov. 20, 1959 FIG. 5

FIG. 5

FIG. 4

FRED G. WILLIAMS JR.

INVENTOR.

ATTORNEYS United States Patent 3,050,239 CENTRIFUGE APPARATUS Fred G.Williams, Jr., Redwood City, Calif., assignor to Beckman Instruments,Inc., a corporation of California Filed Nov. 20, 1959, Ser. No. 854,2814 Claims. (Cl. 233-24) This invention relates generally to a centrifugeapparatus and more particularly to a centrifuge apparatus suitable formicrochemical analysis.

In prior art centrifuge apparatus, the liquid to be centrifuged iscontained in a tube which, in turn, is supported in a Well formed in ametal rotor or in metal buckets carried by a supporting structure. Toprovide a structure sufficiently strong to support both liquid and tube,a heavy rotor or heavy buckets and supporting structure are required.The inertia of conventional centrifuge rotors is much greater than thatcontributed by the liquid column itself. In sedimentation of relativelylarge particles, such as precipitates and blood cells, the accelerationand deceleration time of a conventional rotor is often as great orgreater than the actual time necessary for sedimentation.

It is a general object of the present invention to provide a centrifugeapparatus including a rotor having minimum inertia.

It is another object of the present invention to provide a centrifugerotor whose diameter is less than the minimum radius at whichcentrifugation occurs.

It is a further object of the present invention to provide a centrifugerotor which is adapted to support centrifuge tubes from their open end.

It is a further object of the present invention to pro vide a centrifugerotor which is economical of materials, simple to manufacture, andrepresents an extreme of compactness, portability, and simplicity ofmanipulation.

These and other objects of the invention will become more clearlyapparent from the following description when taken in conjunction withthe accompanying drawmg.

Referring to the drawing:

FIGURE 1 is an elevational view, partly in section, of a centrifugeapparatus in accordance with the invention;

FIGURE 2 shows a modified rotor for the centrifuge apparatus of FIGURE1;

FIGURE 3 is an enlarged view of the rotor of FIG- URE 1;

FIGURE 4 is a sectional view taken along the line 44 of FIGURE 3;

FIGURE 5 shows a centrifuge tube suitable for use in the apparatus ofthe present invention; and

FIGURE 6 shows a plurality of tubes mounted on a support.

The centrifuge apparatus of the present invention includes a housing 11which houses a drive motor 12 for driving the rotor assembly 13.Controls 14 are provided for controlling the speed of rotation. Themotor shaft 16 extends upwardly through a bowl 17 which forms a rotorchamber to receive and support the rotor 18. A set screw 19 is providedfor adjusting the position of the rotor on the shaft 16. The bowl 17 isseated on the rim 2'1 carried at the upper end of the housing 11 and acover 22 is provided to close the top of the bowl. The cover may belifted until the end 23 is accommodated in the longitudinal slot 24. Thecover is then held open to provide access to the rotor chamber.

Referring particularly to FIGURES 3 and 4, the rotor includes aplurality of longitudinal grooves 26 which are provided with slots 27.The longitudinal grooves are spaced so that the rotor is balanced, forexample the "ice slots may be equally spaced about the circumference ofthe rotor. The rotor is locked to the shaft 16 by set screws 28.

Each pair of spaced slots 27 accommodates a tube support 31. Eachsupport is provided with a plurality of tube receiving apertures whichreceive the tubes 32. The open ends of the tubes 32 are provided with arim 33 which rides against the support 31. The closed end extendsoutwardly from the support. The tube 32 may be provided with a stopperor closure 34, FIGURE 5, to prevent loss of sample when the rotor isstationary. The holder with tubes is placed in the accommodating slots27 and the various tubes are disposed, FIGURE 1 for centrifugation. Itis observed that, in general, the maximum diameter of the rotor is onlyslightly greater than the diameter of the circle including the rims ofthe tubes. Thus, it is apparent that the inertia of the rotor is at aminimum while affording suflicient support for the tubes.

It is observed that the tubes may be readily mounted in the support 31and that a complete assembly of the tubes and support may beconveniently placed on the rotor for a centrifugation operation.

The tubes 32 may be made of plastics and can be rotated at speeds whichcause stresses in the tubes which are near the limits of their strength.In the event of failure of the light, plastic tube due to the stresses,there is little hazard to personnel.

The bowl 17 is provided to prevent scattering of materials should therebe a breakage. Greater fields can be developed using plastic tubes thanare available in so-called high speed centrifuges. With metal tubes, theperformance of ultra centrifuges can be approached with the apparatus ofthe present invention while providing short acceleration anddeceleration times. The tubes can be easily separated from the support;they are inexpensive and may be disposed after use.

The sample tubes 32 may have an internal diameter such that if they aremaintained in a horizontal position, the liquid to be operated upon willnot flow outwardly from the open end because of surface tension.However, as previously described, if the tubes are of greater diameter,the stoppers 34 are provided for sealing the ends until centrifugationtakes place.

In certain applications, it may be desirable to support the tubesvertically until the apparatus begins to gain speed, at which time thetubes are disposed horizontally. Such a rotor may be of the type shownin FIGURE 2. That is, the rotor is cup-shaped and adapted to beaccommodated on and suitably secured to the driving shaft 16. Forexample, a set screw 41 may be employed to secure the rotor to theshaft. The rotor is slotted at equally spaced points and is adapted toreceive the tube 32. The slots extend from the horizontal portion of therotor upwardly and have a portion which is vertical. Thus, when therotor is standing still, the tube hangs vertically as shown in dottedoutline at 42, while after the centrifuge begins to rotate, the tubewill achieve a horizontal position as shown at 43.

Thus, it is seen that there is provided a centrifuge rotor which has adiameter exclusive of the centrifuge tubes which is near the minimumradius at which centrifugation in the liquid column occurs. The tubesare provided with rims which serve to support the tubes from asupporting member, for example, a support plate or from a rotorincluding holes or slots. The rotor has an external diameter onlyslightly greater than the diameter of a circle including the open end ofthe tubes.

I claim:

1. A centrifuge rotor assembly for supporting centrifuge tubesincluding, a rotor member adapted to rotate about its axis and havingformed therein a plurality of symmetrically disposed elongatedrectilinear undercut slots in its outer peripheral surface with theirlongitudinal axes substantially parallel to the axis of the rotor, eachof said slots having an axially facing open end, and a plurality ofelongated tube supports each having at least one aperture therethroughto receive a centrifuge tube and support the same by its normally openend, said tube supports being removably positioned substantiallyentirely within said undercut slots through the open ends thereof withsaid apertures extending generally radially to support said tubes toextend radially outwardly from the rotor member.

2. A centrifuge assembly comprising elongated separation tubes eachhaving an open end and a closed end, said tubes including a laterallyextending rim at the normally open end, a rotor member adapted to rotateabout its axis and having formed therein a plurality of symmetricallydisposed elongated rectilinear undercut slots in its outer peripheralsurface with their longitudinal axes substantially parallel to the axisof the rotor, each of said slots having an axially facing open upperend, a plurality of tube supports each having at least one aperturetherethrough to receive one of said tubes and support the same from itsrim, said tube supports being inser-table into said undercut slots fromthe upper end thereof to support the same from the rotor member wherebyto support tubes to extend radially outwardly from the rotor member.

3. A centrifuge assembly comprising a housing, a centrifuge bowl carriedby said housing, a drive motor disposed said housing and having a driveshaft extending into said bowl, a rotor member adapted to rotate aboutits axis having at least one elongated rectilinear undercut slot in itsouter peripheral surface and with its longitudinal axis substantiallyparallel to the rotor member disposed in said bowl and carried by saiddrive shaft, said slot having an axially facing open upper end, at leastone elongated tube having an open end and a closed end, said tubeincluding a laterally extending rim at its open end, a tube supporthaving at least one aperture, therethrough to receive said tube andsupport the same solely from the rim, said tube support being insertablewithin said undercut slot through the upper ends to support the tube toextend radially outwardly from the motor.

4. Apparatus as in claim 1 wherein said tube supports are each providedwith a plurality of spaced apertures for supporting a plurality of tubesfrom said rotor member, whereby the tubes are longitudinally spacedalong said rotor member.

References'Cited in the file of this patent UNITED STATES PATENTS330,779 Frederiksen et a1. Nov. 17, 1885 330,780 Frederiksen et a1 Nov.17, 1885 486,390 Berg Nov. 15, 1892 998,529 Ketcham July 18, 19111,839,944 Barthels Jan. 5, 1932 2,110,308 Nelson Mar. 8, 1938 2,560,988Ruda July 17, 1951 2,604,261 Silverstolpe July 22, 1952 2,720,711 Grayet a1 Oct. 18, 1955 2,817,970 Whitby Dec. 31, 1957 I 2,854,189 GarrettSept. 30, 1958 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONPatent No. 3,050,239 August 21, 1962 Fred G. Williams Jr.

Column 4, line 11 for "motor" read rotor Signed and sealed this 5th dayof February 1963.

(SEAL) Attest:

ERNEST W SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents

